Given range x and y you have to find number of champ numbers between these range

Champ numbers are:

numbers in which every digit is distinct

All digits are less than 5

Can anyone solve this question ???

X and y are large 10^9

Given range x and y you have to find number of champ numbers between these range

Champ numbers are:

numbers in which every digit is distinct

All digits are less than 5

Can anyone solve this question ???

X and y are large 10^9

Realise that there is an upper bound on the largest possible *champ* number, and that it is pretty small. The largest possible *champ* number is 43210.

Thanks brother done!!

Actually I could not think before that champ numbers in range (1-10^9) is only 1650 in total so I should better generate them instead of checking all